2% fee's will solve all the BTC problems: slow-confirmation-risk, seller-risk, etc. Mom&Pop will use it. *Not* because BTC is so great but because there is no reason not to use it (a bit like PayPal).
With a 2% fee there is absolutely no reason to use it. Merchants gain nothing but added complexity and expense. They can simply keep using PayPal. The largest advantage for merchants is a significant boost to their net margins by the removal of the 2% overhead by bypassing the credit card network. It makes no sense to bypass the credit card network to pay the same amount in fees to a different third party. Merchant adoption would be essentially zero.